Today, a panoply of prominent tech and Internet leaders is taking a very public stand against a controversial initiative before California voters, which would eliminate the current legal right of same-sex couples to marry.

Forming a group and taking out a full-page ad in the San Jose Mercury News tomorrow, the execs hope to convince voters to reject Proposition 8, which is titled “Eliminates Right of Same-Sex Couples to Marry.”

Silicon Valley has had a long history of supporting gay rights. And recently, Google (GOOG) Co-Founder Sergey Brin has made a strong statement opposing Proposition 8, while Apple (AAPL) gave $100,000 to help defeat it.

The honorary co-chairs of “Silicon Valley Leaders Say NO on Proposition 8″ include: Brin; Bill Campbell, Chairman, Intuit; David Filo, Founder, Yahoo; Chuck Geschke, Founder and Chairman, Adobe Systems; John Morgridge, Former CEO and Chairman, Cisco Systems; Pierre Omidyar, Founder and Chairman, eBay; Sheryl Sandberg, COO, Facebook; Eric Schmidt, CEO, Google; and Jerry Yang, Founder, Yahoo.

In a statement in a press release set to go out this morning, Yang said: “Silicon Valley has always been an example for the rest of the country of how diversity and openness help to drive innovation and value creation. This divisive measure is the antithesis of those values that make Silicon Valley so unique.”

An ad the group–which also includes star venture capitalist Mike Moritz of Sequoia Capital, as well as Palm Founders Donna Dubinsky and Jeff Hawkins, and many others–is putting out tomorrow in the Mercury News reads:

Silicon Valley Leaders Urge You to Stand for Equality.
Vote No on Proposition 8.

As Silicon Valley leaders, we are committed to equality and fairness. We are opposed to Proposition 8 because it would change our state constitution to take away rights from one group of people. It would set our state, and our country, back in the fight for fundamental fairness and equal rights.

Please join us by reaching out to friends and neighbors and asking them to stand for fairness: Vote No on Proposition 8 on November 4th.”

(The ad and a longer list of tech leaders opposing Proposition 8 is below.)

If passed by a majority of voters, the California Constitution would be amended to include a new section stating “only marriage between a man and a woman is valid or recognized in California.”

Earlier this year, the California Supreme Court held that same-sex couples have a constitutional right to marry under the state’s constitution.

Former California State Controller and former exec at eBay Steve Westly noted that his own interracial marriage was once illegal, which is one of the reasons he was opposing Propostition 8.

“It really is the civil rights issue of the day … people stood up and fought for people like me and now it is time to stand up for others,” said Westly, who was an early supporter of gay marriage and is said to be eyeing a run for governor of the state. “While this is a polarizing issue, it is mind-boggling to me not to support the right of any two adults who love each other to marry.”

One thing is certain–the issue is indeed polarizing. Currently, the vote on Proposition 8 is very close, and a huge amount of money–more than $60 million–has been spent by both sides in the battle, which is considered one of the most contentious and high-profile in the nation.

Here is the ad (click on the image to make it larger):

LEADERS (partial list):
Deborah Barber, Principal, Jackson Hole Group
John Battelle, Chairman and CEO, Federated Media
Larry Birenbaum, Former Senior Vice President, Cisco Systems
Lorna Borenstein, President, Move
Larry Brilliant, Executive Director, Google.org
Owen Byrd, President, Byrd Development
John Chisholm, Chairman and CEO, CustomerSat
Barry Cinnamon, CEO, Akeena Solar
Tod Cohen, Director of Government Affairs, eBay
LaDoris Cordell, Administrator, Stanford University
Sue Decker, President, Yahoo!
Jack Dorsey, Chairman, Twitter
David Drummond, SVP, Corporate Development & Chief Legal Officer, Google
Donna Dubinsky, CEO, Numenta
Alan Eustace, SVP, Engineering and Research, Google
Naomi Fine, President & CEO, Pro-Tec Data
Rachel Glaser COO/CFO, Reunion.com
Carl Guardino, President and CEO, Silicon Valley Leadership Group
Andre Haddad, CEO, Shopping.com
Jeff Hawkins, co-Founder Palm, Handspring, and Numenta
David Karnstedt, Investor
Scott Kaspick, Managing Director, Kaspick & Co.
Steve Kirsch, Serial Entrepreneur
John Koza, CEO, Third Millennium
Ross LaJeunesse, Head of State Policy Western US, Google
Gary Lauder, Managing Partner, Lauder Partners Venture Capital
Laura Lauder, General Partner, Lauder Partners Venture Capital
Len Lehman, Investor
John Luongo, Former CEO, Vantive Corporation
Roger McNamee, Managing Director & co-Founder, Elevation Partners
Ken McNeely, President, AT&T California
Michael Moritz, Partner, Sequoia Capital
Susan Packard Orr, CEO, Telosa Software
Randy Pond, Executive Vice President, Cisco Systems
Amy Rao, Founder & CEO, Integrated Archive Systems
Jana Rich, Managing Director, Russell Reynolds
Miriam Rivera, Former Vice President and Deputy General Counsel, Google
Dan Rosensweig, Investor
Dan Rubin, Partner, Alloy Ventures
Hilary Schneider, Executive Vice President US Region, Yahoo
Len Shustek, Chairman, Computer History Museum
Jeff Skoll, Former President, eBay Inc.
Stephanie Tilenius, SVP, eBay North America
Joy Weiss, President and CEO, Dust Networks
Steve Westly, former California State Controller & former SVP eBay
Evan Williams, CEO, Twitter

[UPDATED on 11/05/08] In the interest of full disclosure, I am obviously not a supporter of Proposition 8. And, after I wrote this piece and hours before it passed last night, I got married in California under its recent same-sex marriage law, which the initiative has now overturned. It is still legally unclear what that will mean for people like me who married before Proposition 8 was passed, as it is not retroactive; as of now, the marriages remain valid. In any case, please see this disclosure related to me here.

I’m going to use my $100 rebate I get from the I-had-to-have-it-before-my-brother iPhone to get one! And I’ll even have a dollar left over for a refreshing can of soda.

Watch Colligan explain here:

Hopefully, the Centro will do a little better than Palm’s Foleo, which was demoed at our D5 and was dumped before the launch.

And, as an added bonus, here is that Foleo demo video by Jeff Hawkins:

Hawkins showed off the device, pictured here, which was supposed to go on sale this summer for $499, at D5 for the first time. It was greeted with less than enthusiastic acclaim by the elite tech crowd. The problem: Too large and heavy for so few features.

You be the judge after you see the video, but our own live blogger John Paczkowski even suggested at the time that it might get the unfortunate moniker “Fooleo.”

Given that Palm will be taking a $10 million charge for Foleo’s cancellation, that prediction looks pretty accurate now.

By way of background, D: All Things Digital, the annual tech and media conference Walt Mossberg and I host, has been sold out with a long wait list every year we have put it on.

That has meant only a few hundred people can see the interviews and also demos we do live onstage with some of the tech and media industry’s most interesting and important players and products.

The lineups have included Microsoft’s Bill Gates and Apple’s Steve Jobs, as well as Eric Schmidt of Google, IAC’s Barry Diller, Meg Whitman of eBay, Cisco’s John Chambers and many others.

And we’ve demoed stuff like the Treo when it first came out, as well as digital toilets, Wi-Fi phones and much more.

We usually post the photos and videos of the interviews and demos six or more months after they take place on a separate conference site. This year, our Digital Daily’s John Paczkowski liveblogged and also posted video highlights from all of the sessions immediately on our newly launched site here.

Now, we are posting videos of every session of the 2007 conference here, in full, and we have made all our photo galleries, hosted by SmugMug and mostly shot by our fabulous Asa Mathat, public too. You can also access our videos via the site’s master player here.

Every day, I am going to highlight a different interview or demo from the conference.

Here’s the Foleo, R.I.P.:

So here’s one of my movies to show you how we prepare for the annual conference, which is highlighted this year by a joint interview with Microsoft’s Bill Gates and Apple’s Steve Jobs, the twin icons of the tech industry.

We’ll kick off the conference tomorrow night with an interview with Sen. John McCain, who is in the race to become the Republican nominee for president of the United States. We will talk to him about that, as well as the war in Iraq, but also hope to discuss a plethora of digital issues with him. McCain is one of the few politicians who knows a thing or two about the media, telecom and Web sectors.

Other interviewees on Wednesday and Thursday include: Microsoft CEO Steve Ballmer; CBS CEO Les Moonves; News Corp. President Peter Chernin; Cisco CEO John Chambers; former AOL CEO Steve Case, who will talk about his new company, Revolution; famed director and producer George Lucas; Time Inc. CEO Ann Moore; Google CEO Eric Schmidt; YouTube founders Steve Chen and Chad Hurley; Philippe Dauman, CEO of Viacom; and space tourist (and former Microsoft exec) Charles Simonyi.

We’ll also have demos from tech players like Palm legend Jeff Hawkins and others. And we are also excited to have singer/songwriter Jill Sobule, who will perform several times throughout.

We’ll have full coverage of D5 on our site, starting tomorrow night, including liveblogging by Digital Daily’s John Paczkowski, pictures, video excerpts and more.